OpenCV 视频中的模板匹配

import cv2
import matplotlib.pyplot as plt
import numpy as np

template = cv2.imread('face_template.png',cv2.IMREAD_COLOR)
template = cv2.cvtColor(template,cv2.COLOR_BGR2GRAY)
print(template.shape)
vc = cv2.VideoCapture('test.mp4')
#检测打开是否正确
if vc.isOpened():
    open,frame = vc.read()
else:
    open = False


while open:
    ret,frame = vc.read()
    if frame is None:
        break
    if ret ==True:
        gray = cv2.cvtColor(frame,cv2.COLOR_BGR2GRAY)
        gray = cv2.pyrDown(gray)
       # gray = cv2.pyrDown(gray)
        print(gray.shape)
        w,h = gray.shape[:2]
        res = cv2.matchTemplate(gray, template, cv2.TM_CCOEFF_NORMED)
        threshold = 0.8
        # 取匹配程度大于80%的坐标
        loc = np.where(res >= threshold)
        for pt in zip(*loc[::-1]):  # *号表示可选参数
            bottom_right = (pt[0] + w, pt[1] + h)
            cv2.rectangle(gray, pt, bottom_right, (255, 0, 0), 1)

        cv2.imshow('result',gray)

        if cv2.waitKey(1)  &0xFF == 27:
            break